The promise of transparent electronics: Windscreens that double up as displays

A transparent conductor is a contradiction of sorts, as properties that allow transparency usually make a material an insulator.

Transparency and conductivity are two of the most useful properties of materials, being the foundation of multibillion-dollar industries. What if we could combine the two?

Think of a window that lets light through while also powering a building. Think also of displays that are transparent, like your car windscreen that suddenly lights up to show you an urgent message. Engineers have dreamt of such materials for about a decade, from the time when the first such material was made. Recent research has thrown up fascinating possibilities for transparent electronics, with some cool products not too far into the future.

Two research papers illustrate this point. Researchers at Stanford University and the University of Nebraska-Lincoln made the world's fastest organic transistor. The Swiss Federal Institute of Technology made a transistor so thin that it can wrap around a human hair. Both are just proof of concepts, but the scientists have also demonstrated real applications. The Swiss group put the transistor on top of a contact lens, suggesting ways of monitoring the eye function — ocular pressure, for example — continuously.

Medical applications of transparent electronics are plenty, but others are nearer to us. A transparent conductor is a contradiction of sorts, as properties that allow transparency usually make a material an insulator. Yet the first such material, zinc oxide, was made in 2003 by researchers at Oregon State University.

Since then, more than 30 different transparent semiconductors have been made. While they are not perfectly transparent, they let enough light through them to be considered for many semiconductor applications. Some researchers have made solar cells that are nearly completely transparent.

An MIT startup called Ubiquitous Energy uses a clever trick: coat glass with a material that can absorb infrared and ultraviolet rays while allowing visible light to pass through.

The glass then remains transparent, while the absorbed energy can be used to generate electricity. Using some sophisticated engineering, they have developed a sheet of transparent glass with material that can absorb non-visible light and generate electricity. The founders think that the current efficiency of this glass can be racked up to 12%, which should be enough to provide one-third the energy required for a skyscraper.

The Future is Clear?

This work will take some time to be commercialised, if at all. Fascinating technologies often founder in the marketplace because of poor economics and inconsistent quality. Yet recent research is very promising, as scientists have demonstrated a variety of technologies over the last year or two.

This is why market researchers have started eyeing this field, and think that transparent electronics will soon create smart windows and displays, wearable electronics, solar panels, lighting and so on. Ubiquitous Energy is attempting to put their seethrough material on mobile phones as well. Car-makers are interested in windscreens that can double up as displays. Medical engineers are looking to integrate electronics with the human body.

By using a novel process, Stanford and Nebraska-Lincoln researchers created thin-film organic transistors that are five times as fast as existing organic transistors. They have reportedly shown that it is possible to make organic transistors that are 90% transparent to the human eye. But transparent electronics still requires a process that can create reliable circuitry at low costs. The first transparent electronics product could be a smartphone that may come out by year-end. It will be a crude device when compared to what will come over the decade.